1. Field of the Invention
The present invention relates to a far-end control method with a security mechanism including confirming matching of a identification code transmitted by a host through a PSTN (Public switched telephone network) with a predetermined value stored in an I/O control device to activate a connection of a mobile internet between these two ends, and thus to reduce damage caused by line occupied from a hacker invasion or error signal transmission, and also reduce the cost and power consumption without connecting the mobile internet between these two ends all the time.
2. Description of Related Art
The rapid advancement of information technology and continuously developing telecommunication technology have led to creation of wired telephone, pager and mobile phone of first, second and third generations. With the rapid development in technology, the telecommunication companies developed the telecommunication technology of 3G, 3.5G and 4G to broaden the appliance range in the future mobile phone communication. Accordingly, the content and the appliance of the mobile phone communication have expanded more to even connect with the mobile internet with upgraded digital transmission function. The upgraded band width of the mobile internet enables many industrial control equipment and electronic mechanics to execute the related operations of the far-end control with the mobile internet technology. Particularly for remote area or region with difficulty of arranging wiring, the company uses an internal computer to mutually transmit the information or data with the industrial control equipment of the remote area through the mobile internet. However, such industrial control equipment is not equipped with transmitting or receiving function of the mobile internet, and therefore, mutual communication with the computer is not direct and an I/O control device with the transmitting or receiving function of the mobile internet is required for serving a bridge for communication between the computer and the industrial control equipment. Thus, through the I/O control device and the industrial control equipment, the computer can reading data from the electric meter, company gate inhibition from the far-end water gate opening and closing, power supply control to the remote area and others. But such I/O control device does not have the mechanism to prevent the unauthorized invasion or monitoring; and the damage can be serious if hacker invades into the system to interrupt the communication or to make the fault signal transmission during the process of the mobile internet and the communication. For example, the far-end is unable to read the data of the electric meter if the band width of reading the number from the electric meter is fully occupied by the hacker; all the company's information, business secrets and properties will be facing the traumatic threat if the gate inhibition is invaded; if the water gate opening and closing system is invaded and the water level is over the predetermined level, the water gate may lose the normal function of opening for releasing the water or to discharge the flood when the water level hasn't reached the predetermined level, and such unexpected situation can cause mass of the damages.
Furthermore, the above-mentioned mobile internet technology uses the dynamic IP address, which is variable when reconnecting after disconnection, thus to have the advantage of being not easy to be locked up by a hacker. But because the computer cannot retrieve the new IP address of the I/O control device after the I/O control device disconnection and reconnection with the mobile internet of the base, the computer cannot automatically reconnect with the I/O control device. In such conventional structure, the solution for preventing the disconnection between the I/O control device with the mobile internet of the base is to transmit some meaningless package to the base by the I/O control device at a certain time in order to hold on to the present IP address. Somehow, even such transmission by a static IP address still has the risk of being locked up by a hacker to cause the above damages. Besides, the mobile internet usually charges according to the packet of the transmission. When the system is being hacked, the industrial control equipment will repeatedly send out packages through the I/O control device increasing the cost of the company. On the other hand, in this conventional structure, the I/O control device has to keep transmitting the package to the base for staying on the line, and the cost on the power consumption of the I/O control device is correspondingly high.
Therefore, the method for the companies to keep out the unauthorized invasion into the mobile internet usually is to apply a virtual intranet by the internet service provider (ISP), for example the Cingular, Verizon, Chunghwa Telecom, Taiwan Mobile, Far Eastone Telecommunications Company or others, to own an exclusive access point name (APN), thus the company can use the particular IP address in the exclusive APN to combine with the firewall for filtering at the IP address and the entrance to further process the network connection between the computer and the far-end industrial control equipment. Even though this method can effectively prevent the hacker invasion, but the application cost is too high; based on the fact that different areas have different density, so the company has to apply the exclusive APNs from different ISPs. The system of each ISP is independent and incompatible thus difficult for the company to integrate all the information transmission.
Therefore, how to overcome the above conventional defects is an important issue for the manufacturers in the field.